2014 DTC Annual Symposium

The annual Desert Tortoise Council Symposium was full of interesting topics and discussions. This year, Kathy Simon (Ironwood) chaired the final session on desert tortoise connectivity, which included presentations from Ken Nussear (USGS), Roy Averill-Murray (DTRO), Chris Blandford (Ironwood) and Rick Simon (Cordoba Corporation). Roy Averill-Murray and the DTRO recently produced guidance documents with regard to the importance of demographic connectivity in terms of recovery efforts. Conserving functional linkages between tortoise conservation areas strengthens the network of conserved lands and helps mitigate against the adverse of effects of population declines, stochastic events, and population isolation. Roy Averill-Murray presented a new method of modeling population dynamics within a spatial context to better understand how local populations or habitat patches contribute to long-term, regional population viability. Ken Nussear introduced a new technique of identifying contact networks among individual tortoises within linkages under study. His study sites consisted of high-elevation, relatively narrow passes that potentially bridge occupied habitat located in neighboring valleys. The study is still progressing, yet there were already evident tortoise-to-tortoise contact networks that imply connectivity within the study areas. Chris Blandford presented the results of a comprehensive assessment of existing habitat connectivity within and through Ivanpah Valley, which has recently been home to several large-scale solar projects. In 2011, we set out to assess in further detail the existing conditions of habitat connectivity within and along the periphery of Ivanpah Valley, which led to the aforementioned study led by Ken Nussear. Through a combination of field data collection and spatial analysis, we developed maps and written description of existing habitat connectivity, including the potential for genetic and demographic connectivity, across existing geographic and anthropogenic features. Rick Simon, a civil engineer specializing in transportation, presented an engineering perspective on what the requirements are for constructing underpasses and bridges to facilitate connectivity, what the transportation agencies will consider in approving such facilities, and what the issues are involved in the design, construction, and maintenance of such facilities. His presentation conveyed the issues and requirements involved in providing connectivity across transportation corridors, which are valuable to biologists and land managers in planning, coordinating, and implementing these facilities on future projects.